coreutils: get the uptime program to work

coreutils configure script needs to know whether /proc/uptime is
available, but this is not possible in a cross-compilation
context. This leads to an uptime program that fails to work on the
target, as it has been compiled without /proc/uptime reading support.

This commit fixes that by telling coreutils at configure time that
/proc/uptime will be available on the target (which seems to be a
reasonable assumption on Linux systems).

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tested-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/coreutils/coreutils.mk

@@ -57,6 +57,7 @@ COREUTILS_CONF_ENV = ac_cv_c_restrict=no \
 		gl_cv_func_working_mkstemp=yes \
 		gl_cv_func_working_utimes=yes \
 		gl_getline_needs_run_time_check=no \
+		gl_cv_have_proc_uptime=yes \
 		utils_cv_localtime_cache=no \
 		PERL=missing